Biochemistry, Doppler echocardiography, and electrocardiography evaluation in captive owl monkeys (Aotus sp).

BACKGROUND: The cardiovascular system of owl monkeys has been studied due to frequent postmortem findings of heart disease in asymptomatic animals. The silent aspect and the difficulty of early diagnosis intensify the importance of studying the cardiovascular system in this species. METHODS: Echocardiogram evaluation was carried out on 60 animals, grouped into suspect or non-suspect of having heart diseases, and evaluated through electrocardiogram, hematology, and biochemical tests. RESULTS: Doppler echocardiography indicated two animals with suspicion of left ventricular hypertrophy and eight with dilated cardiomyopathy. Suspect animals had higher cardiac measurements and reduced shortening fraction. Troponin I was detectable in two animals (0.128 ng/mL and 0.584 ng/mL), and serum albumin concentration was significantly higher in non-suspect animals (P < .05). CONCLUSIONS: The importance of echocardiographic measurements of IVSd, IVSs, LVIDd, LVIDs, LVPWd, LVPWs, LA, EF, and FS in the cardiac evaluation of captive owl monkeys was evidenced.

Topography of the medullary cone of the feline night monkey: Clinical implications in epidural anesthesia / Topografia do cone medular do macaco-da-noite: auxiliando a abordagem peridural

Feline night monkey (Aotus azarae infulatus) is an arboreal primate that sleeps during the day hidden among branches of trees, leaving its hideout after nightfall. Little is known about the morphology of these animals, which leads to some difficulty in clinical and surgical approaches, as there has been substantial growth in the veterinarian’s role in maintaining the health and well-being of wildlife. Thus, we sought to investigate the topography and morphometry of the medullary cone, a small portion of the nervous system of the feline night monkey, which is of paramount importance in approaches for epidural anesthesia. Specimens from five young females were used, each with eight lumbar vertebrae, three sacral vertebrae, and a medullary cone with an average length of 7.5 cm, located between L5 and S3. Based on this finding, we suggest that a probable site for the application of epidural anesthesia is the space between S3 and Cc1.

O macaco-da-noite (Aotus azarae infulatus) é um animal arborícola que dorme durante o dia escondido entre os ramos, saindo do esconderijo após o anoitecer. Pouco se sabe sobre a morfologia destes animais, o que gera certa dificuldade nas abordagens clínico-cirúrgicas, uma vez que cresce substancialmente o papel do médico veterinário nas questões de saúde e bem-estar de animais selvagens. Visando contribuir com esses profissionais, buscou-se investigar a topografia e morfometria de uma pequena porção do sistema nervoso do macaco-da-noite, o cone medular, que é de suma importância nas abordagens quanto à anestesia peridural. Foram utilizados cinco espécimes fêmeas, jovens, de macaco-da-noite, que apresentavam oito vértebras lombares e três vértebras sacrais, e cone medular possuindo em média de 7,5 cm de comprimento, localizando-se entre L5 e S3. Este achado nos leva a sugerir como sítio provável para a aplicação de anestesia epidural, o espaço entre S3 e Cc1.

Topography of the medullary cone of the feline night monkey: Clinical implications in epidural anesthesia / Topografia do cone medular do macaco-da-noite: auxiliando a abordagem peridural

Feline night monkey (Aotus azarae infulatus) is an arboreal primate that sleeps during the day hidden among branches of trees, leaving its hideout after nightfall. Little is known about the morphology of these animals, which leads to some difficulty in clinical and surgical approaches, as there has been substantial growth in the veterinarian's role in maintaining the health and well-being of wildlife. Thus, we sought to investigate the topography and morphometry of the medullary cone, a small portion of the nervous system of the feline night monkey, which is of paramount importance in approaches for epidural anesthesia. Specimens from five young females were used, each with eight lumbar vertebrae, three sacral vertebrae, and a medullary cone with an average length of 7.5 cm, located between L5 and S3. Based on this finding, we suggest that a probable site for the application of epidural anesthesia is the space between S3 and Cc1.

O macaco-da-noite (Aotus azarae infulatus) é um animal arborícola que dorme durante o dia escondido entre os ramos, saindo do esconderijo após o anoitecer. Pouco se sabe sobre a morfologia destes animais, o que gera certa dificuldade nas abordagens clínico-cirúrgicas, uma vez que cresce substancialmente o papel do médico veterinário nas questões de saúde e bem-estar de animais selvagens. Visando contribuir com esses profissionais, buscou-se investigar a topografia e morfometria de uma pequena porção do sistema nervoso do macaco-da-noite, o cone medular, que é de suma importância nas abordagens quanto à anestesia peridural. Foram utilizados cinco espécimes fêmeas, jovens, de macaco-da-noite, que apresentavam oito vértebras lombares e três vértebras sacrais, e cone medular possuindo em média de 7,5 cm de comprimento, localizando-se entre L5 e S3. Este achado nos leva a sugerir como sítio provável para a aplicação de anestesia epidural, o espaço entre S3 e Cc1.

Morphological analyses of the retinal photoreceptor cells in the nocturnally adapted owl monkeys.

Owl monkeys are the only one species possessing the nocturnal lifestyles among the simian monkeys. Their eyes and retinas have been interested associating with the nocturnal adaptation. We examined the cellular specificity and electroretinogram (ERG) reactivity in the retina of the owl monkeys by comparison with the squirrel monkeys, taxonomically close-species and expressing diurnal behavior. Owl monkeys did not have clear structure of the foveal pit by the funduscope, whereas the retinal wholemount specimens indicated a small-condensed spot of the ganglion cells. There were abundant numbers of the rod photoreceptor cells in owl monkeys than those of the squirrel monkeys. However, the owl monkeys' retina did not possess superiority for rod cell-reactivity in the scotopic ERG responses. Scanning electron microscopic observation revealed that the rod cells in owl monkeys' retina had very small-sized inner and outer segments as compared with squirrel monkeys. Owl monkeys showed typical nocturnal traits such as rod-cell dominance. However, the individual photoreceptor cells seemed to be functionally weak for visual capacity, caused from the morphological immaturity at the inner and outer segments.

Histocytological specificities of adrenal cortex in the New World Monkeys, Aotus lemurinus and Saimiri boliviensis.

The New World monkey Aotus spp. (night monkeys) are expected for use of valuable experimental animal with the close species of Saimiri spp. (squirrel monkeys). Saimiri is known to show spontaneous hypercortisolemia, although few reports in Aotus. We compared basic states of blood steroid hormones and histological structure of the adrenal glands in two monkeys. Serum cortisol and ACTH levels were statistically lower in Aotus than Saimiri. Conversely, Aotus adrenocortical area showed significant enlargement, especially at the zona fasciculata. Electron microscopic observation at Aotus fasciculata cells revealed notable accumulation of large lipid droplets and irregular shapes of the mitochondrial cristae. These results suggest potential differences in cellular activities for steroidogenesis between Aotus and Saimiri and experimental usefulness in adrenocortical physiology and pathological models.

Retinotopic organization of extrastriate cortex in the owl monkey--dorsal and lateral areas.

Dense retinotopy data sets were obtained by microelectrode visual receptive field mapping in dorsal and lateral visual cortex of anesthetized owl monkeys. The cortex was then physically flatmounted and stained for myelin or cytochrome oxidase. Retinotopic mapping data were digitized, interpolated to a uniform grid, analyzed using the visual field sign technique-which locally distinguishes mirror image from nonmirror image visual field representations-and correlated with the myelin or cytochrome oxidase patterns. The region between V2 (nonmirror) and MT (nonmirror) contains three areas-DLp (mirror), DLi (nonmirror), and DLa/MTc (mirror). DM (mirror) was thin anteroposteriorly, and its reduced upper field bent somewhat anteriorly away from V2. DI (nonmirror) directly adjoined V2 (nonmirror) and contained only an upper field representation that also adjoined upper field DM (mirror). Retinotopy was used to define area VPP (nonmirror), which adjoins DM anteriorly, area FSTd (mirror), which adjoins MT ventrolaterally, and TP (mirror), which adjoins MT and DLa/MTc dorsoanteriorly. There was additional retinotopic and architectonic evidence for five more subdivisions of dorsal and lateral extrastriate cortex-TA (nonmirror), MSTd (mirror), MSTv (nonmirror), FSTv (nonmirror), and PP (mirror). Our data appear quite similar to data from marmosets, though our field sign-based areal subdivisions are slightly different. The region immediately anterior to the superiorly located central lower visual field V2 varied substantially between individuals, but always contained upper fields immediately touching lower visual field V2. This region appears to vary even more between species. Though we provide a summary diagram, given within- and between-species variation, it should be regarded as a guide to parsing complex retinotopy rather than a literal representation of any individual, or as the only way to agglomerate the complex mosaic of partial upper and lower field, mirror- and nonmirror-image patches into areas.

Ovarian function in captive owl monkeys (Aotus nancymaae and A. vociferans).

BACKGROUND: Ovarian function and morphology of owl monkeys (Aotus spp.) is inadequately known, but it is essential to describe this organ in detail to better understand reproductive patterns of the species. METHODS: This study reports the anatomical and histological features of the ovaries from 41 owl monkeys, considering their reproductive status and parity. RESULTS: The corpora lutea (CL) and reproductive state had a significant effect on ovarian volume. Follicles were observed in both pregnant and non-pregnant subjects. All females in the luteal phase and pregnant females showed at least one cyclic or pregnancy CL. Mean ovulation rate was 1.89 CL/female, and the mean ovum mortality was 37.5%. There were no significant differences in ovarian volume related to parity. CONCLUSIONS: These results contribute to the scarce information available on the reproductive biology of owl monkeys and can aid in the development of biotechnologies involved in assisted reproduction.

Functional morphology of the tubular genital organs in the female owl monkey (Aotus spp.).

BACKGROUND: Studies on reproductive morphology are important to understand the reproductive cycle of non-human primates. METHODS: This study describes the functional morphology of the adult female tubular genital organs in 41 Aotus (12.8 ± 6.8 years old, ranging from 3 to 25 years), with respect to reproductive status and number of parturitions. RESULTS: In females with developing embryos, endometrial glands showed a higher secretion than other females, and the embryo implantation occupied this secretive endometrium. Changes in the thickening, number of layers, and keratinization in the vaginal epithelium suggest that vaginal cytology may be an indicator of the estrous cycle. Non-pregnant multiparous females had a larger uterine body than nulliparous females. Number of parturitions and reproductive state had an impact on tubular genital organs in female owl monkeys. CONCLUSIONS: These results can be useful for the development of biotechnologies of reproduction and for improvement of the management of this species.

Avaliação ultrassonográfica e mensurações das glândulas adrenais em primatas não humanos neotropicais: mico-de-cheiro (Saimiri sciureus), macaco-da-noite (Aotus azarae infulatus) e bugio-ruivo (Alouatta guariba clamitans) / Adrenal glands measurements and ultrasound evaluation in nonhuman primates: squirrel monkey (Saimiri sciureus), owl monkey (Aotus azarae infulatus) and howler monkey (Alouatta guariba clamitans)

As glândulas adrenais possuem funções endócrinas relacionadas a múltiplas funções vitais, estando intimamente relacionadas à capacidade do animal em se adaptar ao estresse. O exame ultrassonográfico é o método diagnóstico de escolha para avaliação das glândulas em diferentes espécies. Considerando a escassa literatura, questiona-se se as doenças adrenais em primatas não humanos são incomuns ou subdiagnosticadas, havendo a hipótese desse fato ser determinado pela falta de parâmetros. Objetivou-se descrever as características ultrassonográficas das glândulas adrenais para três espécies de primatas não humanos mantidas em cativeiro: Saimiri sciureus (mico-de-cheiro), Aotus azarae infulatus (macaco-da-noite) e Alouatta guariba clamitans (bugio-ruivo). Conclui-se que é possível a identificação das glândulas adrenais por meio de exame ultrassonográfico, sendo que os padrões de referência foram estabelecidos com sucesso para as espécies em questão. Ressalta-se que a adequação de animais em ambientes estressantes é frequentemente acompanhada por uma hipertrofia das glândulas adrenais, portanto deve-se levar em consideração que as mensurações realizadas nesse estudo foram estabelecidas em animais de cativeiro...

The adrenal glands have endocrine functions related to multiple vital functions and are closely related to the animal's ability to adapt to stress. The ultrasound is the diagnostic method of choice for evaluation of glands in different species. Considering the scarce literature, one may question whether the adrenal disorders in nonhuman primates are uncommon or underdiagnosed, and a hypothesis exists that this fact is determined by the lack of parameters. The goal is to describe the sonographic features of the adrenal glands for three species of nonhuman primates kept in captivity: squirrel monkey (Saimiri sciureus), owl monkey (Aotus azarae infulatus) and howler monkey (Alouatta guariba clamitans). It is concluded that it is possible to identify the adrenal glands by ultrasound, and the reference standards have been established successfully for the species in question. It is noteworthy that the adaptation of animals in many stressful environments is often accompanied by a hypertrophy of the adrenal glands, so one should take into account that the measurements performed in this study were established in captive animals...

Analysis of follicular events in owl monkeys (Aotus azarai infulatus) using B-mode and Doppler ultrasound.

Ultrasound (B-mode) was used to analyze follicular events in 12 trained female owl monkeys (Aotus azarai infulatus). The animals were examined every 48 hours for over 90 days to measure and map follicular growth in both ovaries and to measure (using Doppler velocimetry) local hemodynamic changes during the peri-ovulatory stage. There were 44 follicular growth events, each with two or three follicular waves, and a mean ± SEM interval between events of 17 ± 1.13 days. There were various hemodynamic changes during follicular growth; both vascular resistance index and pulsatility index decreased during the time when the follicle diameter peaked. Thus, both B-mode and Doppler ultrasound were useful for monitoring ovarian follicular events in owl monkeys.

Renal evaluation of Aotus azarai infulatus by ultrasonography and serum chemistry profile.

This study aimed to characterize anatomical and biochemical properties of owl monkey kidneys in order to provide normal reference values. Sixty-nine Aotus azarai infulatus (45 males and 24 females) were divided into four different age groups (AG1: 3 months-1 year; AG2: 2-3 years; AG3: 4-6 years; and AG4: over 7 years old). The monkeys were evaluated with a serum chemistry profile, focusing on serum creatinine (SCr) and blood urea nitrogen (BUN) and with ultrasound. Mean body mass differed among the age groups. This significance was attributed to AG1 body mass being significantly lower than in AG2 and that in both AG2 and AG3 being significantly lower than in the two older age groups (AG3 and AG4). SCr and BUN concentrations differed significantly between the sexes and SCr level correlated positively with age. In contrast, renal measurements did not differ between males and females. Left and right renal volumes did not differ significantly within age groups, or among AG2, AG3, and AG4. Renal volumes in AG1, however, while not differing from those in AG2, did differ significantly from those in AG3 and AG4. In conclusion, this study provides ultrasonographic reference values for the morphology the kidneys in A. a. infulatus. Evidence is also provided that SCr and BUN levels in owl monkeys are influenced by the sex and age of the individual, factors that should be considered when interpreting test results.

Rensch's rule, Bergmann's effect and adult sexual dimorphism in wild monogamous owl monkeys (Aotus azarai) of Argentina.

Some monogamous primates are characterized by biparental care, territoriality, and a reduced level of physical dimorphism. In others, the relationship between those behavioral patterns and dimorphism is less clear. I tested Bergmann's and Rensch's rules using Aotus spp. body mass data and I characterized the extent of sexual dimorphism in body mass, dental and physical measurements in a socially monogamous owl monkey population (n = 91 adults) from the Argentinean Gran Chaco. A. azarai azarai from the Argentinean Chaco is larger than the more tropical owl monkey species (r = 0.7, N = 6 species), but there is no apparent increase in sexual dimorphism with increased body mass. The body masses of adult male and female A. a. azarai were remarkably similar (Mean = 1.26 kg); there were no marked sex differences in most skeletal measurements, but males had higher and wider upper and lower canines than did females. Body mass and neck circumference were positively and strongly related (r = 0.533, n = 52), and the body mass of adults was not a reliable indicator of their age (r = 0.03, n = 10). The data illustrate the complexities inherent in examining and summarizing within population variation in skeletal and nonskeletal measurements and contribute to a better understanding of the relationships between monogamous behavioral patterns and sexual dimorphism.

Effect of age and number of parturitions on uterine and ovarian variables in owl monkeys.

BACKGROUND: We aimed to evaluate the uterine and ovarian volumes of owl monkeys in different age groups with different numbers of live births and to analyze the interaction between both. METHODS: We performed pelvic ultrasound exams to compare the uterine measurements with weight, age (infant, juvenile, subadult, young adults, and adults) and the number of live births (nulliparous, primiparous, and multiparous) and to compare the ovarian measurements with weight and age. RESULTS AND CONCLUSIONS: The uterine volume (UV) was directly proportional to the number of parturitions, which was the most important factor in the uterine growth of adult females (P < 0.05). The body weight and age of the animals showed a high positive correlation with UV (r = 0.5354, r = 0.6489, P < 0.01), respectively. The volume of the ovaries grew in proportion to the age of the females (P < 0.05). Puberty was the period of greatest uterine and ovarian growth.

Measurement of fetal biparietal diameter in owl monkeys (Aotus nancymaae).

Owl monkeys are New World primates frequently used in biomedical research. Despite the historical difficulty of breeding owl monkeys in captivity, several productive owl monkey breeding colonies exist currently. The animals in the colony we describe here are not timed-pregnant, and determination of gestational age is an important factor in prenatal care. Gestational age of human fetuses is often determined by using transabdominal measurements of fetal biparietal diameter. The purpose of this study was to correlate biparietal diameter measurements with gestational age in owl monkeys. We found that biparietal diameter can be used to accurately predict gestational age in owl monkeys.

The normal and abnormal owl monkey (Aotus sp.) heart: looking at cardiomyopathy changes with echocardiography and electrocardiography.

BACKGROUND: Cardiovascular disease, especially cardiomyopathy, was the major cause of death among owl monkeys (Aotus sp.) at a major colony and threatened colony sustainability. For this study, echocardiography (echo) and electrocardiography (ECG) normal values were established, and cardiomyopathy animals identified. METHODS: Forty-eight owl monkeys were studied, 30 older than 10 years of age ('aged') and 8 of age 5 years ('young'). Eight aged owl monkeys had cardiomyopathy. RESULTS AND CONCLUSIONS: Aged Aotus had increased left ventricular posterior wall thickness over young animals. Left ventricular diameter and ejection fraction appeared to be the best identifying measurements for cardiomyopathy. There were no differences in the ECG.

Meaning of the canine sexual dimorphism in fossil owl monkey, Aotus dindensis from the middle Miocene of La Venta, Colombia.

The owl monkey, Aotus, is the only modern nocturnal anthropoid with monogamous social structure. It has been demonstrated by the fossil species, Aotus dindensis, discovered from La Venta, Colombia, that the Aotus lineage had emerged as early as the middle Miocene (12-15 Ma). The type specimen of A. dindensis, which was discovered in 1986, preserves extremely large orbits, indicating a nocturnal habit. However, a few anatomical traits in living Aotus, such as the lack of a tapetum lucidum, indicates that nocturnality is a secondary adaptation from diurnal ancestry in this genus. Here we report new fossil specimens of A. dindensis from La Venta. The specimens include maxillary teeth and a mandibular fragment preserving lower molars. The detailed analysis of the specimen suggests that A. dindensis exhibits strong sexual dimorphism in the maxillary canine and premolars, which is traditionally associated with intense intermale competition for mates and/or food resources in non-monogamous, diurnal societies. As a result, the new fossil materials of A. dindensis demonstrate the first osteological evidence for the diurnal ancestry of the night monkey, Aotus. Moreover, the coexistence of large orbits and canine dimorphism suggests the presence of mosaic evolution in the craniodental characters of the Aotus lineage.

[Morphologic and genetic differentiation of night monkey (Aotus infulatus, Primates, Platyrrhinians, Cebidae) populations from the right and left banks of Rio Tocantins (Brazil)]. / Différenciation morphologique et génétique des populations de douroucoulis (Aotus infulatus, Primates, Platyrhiniens, Cebidae) provenant des rives droite et gauche du rio Tocantins (Brésil).

The cranial morphology of 28 specimens of night monkeys (genus Aotus) was examined using three-dimensional geometrical morphometrics. New results of the morphological differences between two populations of Aotus infulatus from both banks of the Rio Tocantins are proposed. These morphological results totally agree with the genetic distinction of these populations proposed by Schneider -- and Sampaio --, and probably point out recent rapid evolutive changes for this species. Our morphometric results can be used for taxonomic, but also for medical research, as the susceptibility to malaria of night monkeys is variable between species.

Organization of primary afferent projections to the gracile nucleus of the dorsal column system of primates.

In order to reveal the somatotopic organization of the gracile nucleus of the dorsal column-trigeminal complex, neuroanatomical tracers were injected subcutaneously into various parts of the hindlimb and tail of prosimian galagos, New World monkeys, and Old World monkeys. In most cases, tracers were injected bilaterally, and into more than one body part. In six cases, two different, distinguishable tracers were injected into the same hindlimb. Brainstem and spinal cord sections were processed for tracers transported by cutaneous afferents to terminations in the gracile nuclei. Foci of terminations were related to the cell-cluster architecture of the gracile nuclei in sections processed for cytochrome oxidase or stained for cell bodies (Nissl stain). In all taxa, terminations labeled by the injections were distributed in a patchy fashion along the rostrocaudal length of the ipsilateral gracile nucleus. Terminations were largely but not completely focused within the cytochrome oxidase dense cell clusters. Across taxa, afferents from the tail, foot, lower leg, and upper leg terminated in a mediolateral sequence within the gracile nucleus. Afferents from the glabrous skin of toes 1-5 terminated in a ventromedial to dorsolateral sequence in owl, squirrel, and macaque monkeys, but an altered arrangement was seen in the galagos, with a ventrolateral location for toe 1. The use of two tracers in squirrel monkeys indicated that terminations from adjacent toes formed adjacent and largely segregated patches. Terminations of afferents from the plantar pad (sole) of the foot tended to surround those from the glabrous toes.

Uterine evaluation and gestation diagnosis in owl monkey (Aotus azarai infulatus) using the B mode ultrasound.

BACKGROUND: Gynecological and obstetrical ultrasonography has become an indispensable tool in the routine management, health evaluation and research on captive non-human primates. METHODS: Ultrasound was used to evaluate the uterus and estimate the gestation of owl monkeys. Twelve couples were selected, where five were primiparous and seven multiparous females from the National Primate Center reproductive colony, Ananindeua-PA, Brazil. The procedures were carried out using the GE Logiq 100 MP, equipped with a 7.5 MHz linear probe. RESULTS: The females showed a simple uterus, of elongated shape, regular outline and homogeneous echogenic texture. In the uterine measurements craniocaudal diameter, dorsoventral diameter and uterine volume (UV), significant differences were identified (P < 0.05) between ultrasound examinations of primiparous and multiparous females. The UV showed a positive correlation with the number of births. The gestational sac and the embryonic echo were visible between 28 and 38 days after mating. Between 48 and 68 days after mating, embryonic death was identified in all the gestations. CONCLUSIONS: The chemical (use of tranquilizers) and husbandry factors (capture stress) may be related to the prenatal death. The establishing methods of conditioning the female to the ultrasonographic exam may offer a solution to this problem.

Quantitation of sleep and spinal curvature in an unusually longevous owl monkey (Aotus azarae).

BACKGROUND: A table summarizing the primary literature on 19 species of longevous non-human primates, other than owl monkey, is presented. METHODS: We prospectively quantitated the sleep of a longevous female owl monkey (Aotus azarae), aged >30 years, longitudinally for 2 years and also evaluated the senility-induced change in spinal curvature. RESULTS: The mean daily total sleep time (TST) of this monkey ranged between 790 and 1106 minutes, and was markedly higher in comparison with its female progeny (aged 16 years and used as a control) whose daily TST during the same experimental period ranged between 612 and 822 minutes. CONCLUSIONS: The calculated kyphotic index (KI) of 2.27 for this monkey, compared with the KIs 4.83 and 5.42, for its progeny and female grandprogeny (aged 1 year) respectively, confirmed the prominent spinal curvature.